Recently starting Morrowind for the first time, I was disappointed to find out that I cannot apply poisons or potions with negative effects to my weapons.

I did some quick google-ing and I think I have found a few mods that allow this Oblivion-style potion use, but they are usually part of a much larger mod with many features.

Surely there must exist such a mod on its own. Does it?

Fliggerty tried something like this but had to abandon the project due to being unable to finish it. What mods have you found that added this? Maybe he took the wrong approach.

"Complete Morrowind" lets you make and use poisons.
There's even a modular version for that: http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=2129

EDIT: I guess that's not really a modular version though, it requires CM-Full

I've never tried it though.

Fligg was running into problems applying those poisons to non-thrown weapons, which is what the OP wants I'm guessing. From what he said, it wasn't possible, which is why a mod was never released using it.